Novel heme-containing enzyme possibly involved in lignin degradation by the white-rot fungusJunghuhnia separabilima

The white-rot fungus Junghuhnia separabilima (Pouz.)Ryv, showed high levels of laccase production in cultures supplemented with veratric acid. Laccase, lignin peroxidase and an unknown peroxidase were separated from the extracellular culture fluid using anion-exchange FPLC. Three laccase species, three lignin peroxidases and a novel heme-containing protein were characterized by gel electrophoresis and isoelectric focusing. The new hemoprotein has a molecular mass of 44 kDa, isoelectric point of 3,4 and pH optimum of 5.5 for oxidation of o-dianisidine in the presence of H2O2. However it oxidised diaminobenzidine and guaiacol in the absence of H2O2. Veratryl alcohol and phenol red were not substratesfor this enzyme with or without addition of H2O2 and Mn(II). In addition the enzyme did not produce H2O2.